Where Rapid Urbanization Pushes Homes Into Floodways [Infographic]

Around the world, settlements in flood-prone areas have been expanding faster than the average of newly built cities, towns and villages, a paper released Wednesday in the scientific journal Nature has found. Despite climate change increasing the risk of floods, more people have begun living in these areas, driving up the likeliness of human and economic disaster.

The world region most affected is East Asia and the Pacific, where between 1985 and 2015, the share of settlements at risk of severe flooding increased from 7.8% to 9.5%. Around the world, just 5.2% of all human settlements carry the risk of being inundated by more than 1.5 meters of water in the case of a 100-year flood, which is an event that has the likeliness of 1 in 100 of occurring in any given year. This number was up from 4.3% in 1985.

Countries from the region that has been most likely to build in flood-prone areas even decades ago are numerous among the nations with the highest flood risk of settlements overall. Out of the eight low- and middle-income countries most at risk in 2015, Laos and Bangladesh have shares of extremely flood-prone settlements of upwards of 20%, while in Vietnam, this was upwards of 30%. China had the 7th highest risk of severe flooding of settlements in the report at 9.8%, up from 8.1% in 1985.

While living close to bodies of water is sometimes associated with luxury, it is most often a sign of rapid urbanization and land scarcity in low- and middle-income countries. The authors of the study identify a lack of urban planning and disaster awareness in less developed regions as reasons why flood-prone areas are being settled in these nations when land becomes scarce. The pressure on rapidly growing cities which attract people looking for economic opportunity is causing this effect.

Mitigation is key

According to the study, settlements in high flood risk areas grew by 122% globally between 1985 and 2015, while the average of human settlement expansion worldwide was put at 85.4%. Developed countries have expanded settlements in these areas as well, but they are usually better equipped to mitigate the risk of floods by building dams or seawalls. The report identifies the Netherlands as the country that is technically most at risk of severe flooding in the world, as it is famously build in large parts on land that is located below sea level. However, the nation is also known internationally for its highly specialized flood control measures, once again highlighting that not flood risk by itself, but a combination with a lack of development of counter-measures in lower-income countries are creating a recipe for disaster.

Other high-income nations that live with an elevated flood risk are Japan, Hong Kong, Switzerland, Austria, Croatia, Slovenia and South Korea, among others. This makes Europe the region most riskily settled after those in Asia, albeit with better management in most places. In parts of the Balkans which are classified as middle-income, flood risk of settlements is among the highest in the world—namely in Bosnia and Herzegovina and in Montenegro.

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Charted by Statista